Fix Error 500s with anonymous clones for a project that has moved

Closes #41457

1 files changed, 10 insertions, 3 deletions

diff --git a/lib/gitlab/checks/project_moved.rb b/lib/gitlab/checks/project_moved.rb
index 3a1c0a3455e..c1da2471b54 100644
--- a/lib/gitlab/checks/project_moved.rb
+++ b/lib/gitlab/checks/project_moved.rb
@@ -2,6 +2,7 @@ module Gitlab
   module Checks
     class ProjectMoved
       REDIRECT_NAMESPACE = "redirect_namespace".freeze
+      ANONYMOUS_ID_KEY = 'anonymous'.freeze
 
       def initialize(project, user, redirected_path, protocol)
         @project = project
@@ -22,7 +23,7 @@ module Gitlab
 
       def add_redirect_message
         Gitlab::Redis::SharedState.with do |redis|
-          key = self.class.redirect_message_key(user.id, project.id)
+          key = self.class.redirect_message_key(user_identifier, project.id)
           redis.setex(key, 5.minutes, redirect_message)
         end
       end
@@ -45,8 +46,14 @@ module Gitlab
 
       attr_reader :project, :redirected_path, :protocol, :user
 
-      def self.redirect_message_key(user_id, project_id)
-        "#{REDIRECT_NAMESPACE}:#{user_id}:#{project_id}"
+      def self.redirect_message_key(user_identifier, project_id)
+        "#{REDIRECT_NAMESPACE}:#{user_identifier}:#{project_id}"
+      end
+
+      def user_identifier
+        return ANONYMOUS_ID_KEY unless user.present?
+
+        user.id
       end
 
       def remote_url_message(rejected)